mb_encode_mimeheader

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

mb_encode_mimeheader — Codifica una cadena para un encabezado MIME

Descripción

mb_encode_mimeheader(
    string $string,
    ?string $charset = null,
    ?string $transfer_encoding = null,
    string $newline = "\r\n",
    int $indent = 0
): string

Codifica una string string dada en un encabezado MIME.

Parámetros

string: La string a codificar. Su codificación debería ser idéntica a mb_internal_encoding().
charset: charset es el nombre de la codificación utilizada por la cadena string. El valor por omisión se determina mediante los parámetros actuales de NLS (mbstring.language).
transfer_encoding: transfer_encoding es la codificación de transferencia. Puede ser "B" (Base64) o "Q" (Quoted-Printable). Por omisión, es "B".
newline: newline especifica los finales de línea (EOF: end-of-line) utilizados por mb_encode_mimeheader() para formatear la cadena (una » RFC define la longitud de una cadena a partir de la cual se debe añadir un final de línea. La longitud actual es 74 caracteres). El valor por omisión es "\r\n" (CRLF).
indent: Indentación de la primera línea (número de caracteres en el encabezado antes de string).

Valores devueltos

Una versión convertida de la string en ASCII.

Historial de cambios

Versión	Descripción
8.3.0	Los octetos `NUL` (0) ya no se eliminan durante la codificación en Quoted-Printable, sino que se codifican como `=00`.
8.0.0	`charset` y `transfer_encoding` ahora son nulos.

Ejemplos

Ejemplo #1 Ejemplo con mb_encode_mimeheader()

<?php
$name = "太郎"; // kanji
$mbox = "kru";
$doma = "gtinn.mon";
$addr = '"' . addcslashes(mb_encode_mimeheader($name, "UTF-7", "Q"), '"') . '" <' . $mbox . "@" . $doma . ">";
echo $addr;
?>

El ejemplo anterior mostrará :

"=?UTF-7?Q?+WSqQzg-?=" <[email protected]>

Notas

Nota:
Esta función no está diseñada para cortar líneas en medio de palabras. Este comportamiento puede añadir espacios no deseados en una palabra de la cadena original.

Ver también

mb_decode_mimeheader() - Decodifica un encabezado MIME

Found A Problem?

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User Contributed Notes 10 notes

down

stormflyCUT at hyh dot pl ¶

19 years ago

Some solution for using national chars and have problem with UTF-8 for example in mail subject. Before you use mb_encode_mimeheader with UTF-8 set mb_internal_encoding('UTF-8').

down

nigrez at nius dot waw dot pl ¶

19 years ago

True, function is broken (PHP5.1, encoding from UTF-8 with pl_PL charset). Below is about 15% faster version of proposed _mb_mime_encode. Also it has header more like othe mb_* functions and doesn't trigger any errors/warnings/notices.

<?php

function mb_mime_header($string, $encoding=null, $linefeed="\r\n") {
  if(!$encoding) $encoding = mb_internal_encoding();
  $encoded = '';

  while($length = mb_strlen($string)) {
    $encoded .= "=?$encoding?B?"
             . base64_encode(mb_substr($string,0,24,$encoding))
             . "?=$linefeed";

    $string = mb_substr($string,24,$length,$encoding);
  }

  return $encoded;
}

?>

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gullevek at gullevek dot org ¶

21 years ago

Read this FIRST: http://bugs.php.net/bug.php?id=23192 because mb_encode_mimeheaders is BUGGY!

a work around for the multibyte broken error for too long subjects for ISO-2022-JP:

$pos=0;
$split=36; // after 36 single bytes characters, if then comes MB, it is broken
while ($pos<mb_strlen($string,$encoding))
{
  $output=mb_strimwidth($string,$pos,$split,"",$encoding);
  $pos+=mb_strlen($output,$encoding);
  $_string.=(($_string)?' ':'').mb_encode_mimeheader($output,$encoding);
}
$string=$_string;

is not the best, but it works

down

Anonymous ¶

16 years ago

I could not find a PHP function to MIME encode the name for a n email address.



Input   = "Karl Müller<[email protected]>"

Output = "Karl%20M%FCller<[email protected]>"



I wrote it on my own:



<?php

// required to encode names in email addresses    

// replace " " with "%20"

// replace "ü" with "%FC" 

// replace "%" with "%25"      etc....

// Use "%" as Delimiter for MIME

// Use "=" as Delimiter for Quoted Printable

// Input string must be UTF8 encoded

public static function EncodeMime($Text, $Delimiter)

{

    $Text = utf8_decode($Text);

    $Len  = strlen($Text);

    $Out  = "";

    for ($i=0; $i<$Len; $i++)

    {

        $Chr = substr($Text, $i, 1);

        $Asc = ord($Chr);



        if ($Asc > 0x255) // Unicode not allowed

        {

            $Out .= "?";

        }

        else if ($Chr == " " || $Chr == $Delimiter || $Asc > 127) 

        {

            $Out .= $Delimiter . strtoupper(bin2hex($Chr));

        }

        else $Out .= $Chr;

    }

    return $Out;

}

?>

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tokul at users dot sourceforge dot net ¶

17 years ago

mb_encode_mimeheader() depends on correct mbstring.internal_encoding setting. It tries to convert $str from internal encoding to $charset. If you ignore mbstring internal encoding, function might encode strings incorrectly even when $str character set matches $charset

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gullevek at gullevek dot org ¶

19 years ago

My first post was around 2003, and still the mb_mime_header is broken. It is *NOT* usable with longer subjects, and mostly unusable with anything else than japanese.

iwakura at junx dot org is also not working for me, it produces also some gargabe.

I updated my old function (the one I posted 2003) and I tested it with overlong subjects in UTF-8, ISO-2022-JP (japanese), GB2312 (simplified chinese) and EUC-KR (korean) and I got readable results in thunderbird, mail.app, outlook, etc.

<?php

function _mb_mime_encode($string, $encoding)
{
    $pos = 0;
    // after 36 single bytes characters if then comes MB, it is broken
    // but I trimmed it down to 24, to stay 100% < 76 chars per line
    $split = 24;
    while ($pos < mb_strlen($string, $encoding))
    {
        $output = mb_strimwidth($string, $pos, $split, "", $encoding);
        $pos += mb_strlen($output, $encoding);
        $_string_encoded = "=?".$encoding."?B?".base64_encode($output)."?=";
        if ($_string)
            $_string .= "\r\n";
        $_string .= $_string_encoded;
    }
    $string = $_string;
    return $string;
}

?>

down

paravoid ¶

19 years ago

If mb_ version doesn't work for you in MIME-B mode:

function encode_mimeheader($string, $charset=null, $linefeed="\r\n") {
    if (!$charset)
        $charset = mb_internal_encoding();

    $start = "=?$charset?B?";
    $end = "?=";
    $encoded = '';

    /* Each line must have length <= 75, including $start and $end */
    $length = 75 - strlen($start) - strlen($end);
    /* Average multi-byte ratio */
    $ratio = mb_strlen($string, $charset) / strlen($string);
    /* Base64 has a 4:3 ratio */
    $magic = $avglength = floor(3 * $length * $ratio / 4);

    for ($i=0; $i <= mb_strlen($string, $charset); $i+=$magic) {
        $magic = $avglength;
        $offset = 0;
        /* Recalculate magic for each line to be 100% sure */
        do {
            $magic -= $offset;
            $chunk = mb_substr($string, $i, $magic, $charset);
            $chunk = base64_encode($chunk);
            $offset++;
        } while (strlen($chunk) > $length);
        if ($chunk)
            $encoded .= ' '.$start.$chunk.$end.$linefeed;
    }
    /* Chomp the first space and the last linefeed */
    $encoded = substr($encoded, 1, -strlen($linefeed));

    return $encoded;
}

down

chappy at citromail dot hu ¶

19 years ago

In countries where there's non-us ASCII, it's a very good example, for sending mail:

mb_internal_encoding('iso-8859-2');
setlocale(LC_CTYPE, 'hu_HU');

function encode($str,$charset){
    $str=mb_encode_mimeheader(trim($str),$charset, 'Q', "\n\t");
    return $str;
}

print encode('the text with spec. chars: &#337; &#368; &#336; &#369;, ?','iso-8859-2');

It creates a 7bit string

down

-1

iwakura at junx dot org ¶

19 years ago

i think mb_encode_mimeheader still have bug. here is sample code:

function mb_encode_mimeheader2($string, $encoding = "ISO-2022-JP") {
    $string_array = array();
    $pos = 0;
    $row = 0;
    $mode = 0;
    
    while ($pos < mb_strlen($string)) {
        $word = mb_strimwidth($string, $pos, 1);
        if (!$word) {
            $word = mb_strimwidth($string, $pos, 2);
        }
        if (mb_ereg_match("[ -~]", $word)) {    // ascii
            if ($mode != 1) {
                $row++;
                $mode = 1;
                $string_array[$row] = NULL;
            }
        } else {                                // multibyte
            if ($mode != 2) {
                $row++;
                $mode = 2;
                $string_array[$row] = NULL;
            }
        }
        $string_array[$row] .= $word;
        $pos++;
    }
    
    //echo "<pre>";
    //print_r($string_array);
    //echo "</pre>";
    
    foreach ($string_array as $key => $value) {
        $value = mb_convert_encoding($value, $encoding);
        $string_array[$key] = mb_encode_mimeheader($value, $encoding);
    }
    
    //echo "<pre>";
    //print_r($string_array);
    //echo "</pre>";
    
    return implode("", $string_array);
}

is not the best, but it works

down

-3

mortoray at ecircle-ag dot com ¶

20 years ago

At least for Q encoding, this function is unsafe and does not encode correctly. Raw characters which appear as RFC2047 sequences are simply left as is.

Ex:

mb_encode_mimeheader( '=?iso-8859-1?q?this=20is=20some=20text?=' );

returns '=?iso-8859-1?q?this=20is=20some=20text?='

The exact same string, which is obviously not the encoding for the source string.  That is, mb_encode_mimeheader does not do any type of escaping.

That is, the following condition is not always true:
    mb_decode_mimeheader( mb_encode_mimeheader( $text ) ) == $text

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